Feller bunchers are forestry machines that have a saw head at a front of the machine with a spinning disk at the bottom of the saw head. Cutting teeth are mounted around the spinning disk and are spaced apart. The disk is spun up to operating speed by a hydraulic pump and motor circuit. The saw cuts trees by the kinetic energy through inertia of the disk, instead of hydraulic power. Thus, rotational speed of the disk is needed and recovery of rotational speed is important to the ability to cut trees. Cutting pulls down the speed of the saw by consuming its rotational energy. However, the power drawn by the saw from the hydraulic pump and motor circuit, in order to rotate, varies according to the types of trees being cut, climatic conditions (as the presence of snow or ice can further slow down the rotation of the saw), the diameters of the trees and other operational factors. A power profile designed for worst-case conditions in winter can result in over-consumption of power in summer conditions when power demands to rotate the saw are not as great. Unfortunately, known prior art hydraulic pump and motor circuits power profiles are designed for worst-case scenarios and are not easily adaptable to different operational conditions, thus resulting in power losses.
CA2593368A describes a forestry machine with a felling saw that includes a controller receiving an input signal from a sensor providing an indication of the rotational speed of the saw head. The controller actuates a visual indicator to indicate an approximate rotational speed of the saw head. However, this controller does not adjust the power consumption of the hydraulic pump based on this rotational speed reading.
CA2610223A describes a system for measuring a performance of a forestry machine. The system collects data related to the function of a subsystem of the machine and monitors the variation of this data over time. This data is then reported to the user of the machine through graphic presentation or a display module. However, once again, such a system only collects information and does not use this information in order to more efficiently control power demands of the hydraulic pump and motor circuit that drive the rotation of a felling head saw.
Accordingly, there is a need for a control system for a felling saw and method of control thereof that addresses at least one of the above-mentioned problems.